Kernel panic message
I have this very message on my centos system while trying to boot.in this my several important data.I have also reset the date and time and I suspect some other item(s) need to be set correctly so boot can continue, but I don't knkow which ones. Can anyone instruct me? Here is the last page of messages seen while booting, and I don't know how to retrieve any that scrolled by before these came:

…………..other stuff I can’t see off the screen)

Buffer I/O error on device hdb, logical block 2
Buffer I/O error on device hdb, logical block 3
Buffer I/O error on device hdb, logical block 4
Buffer I/O error on device hdb, logical block 5
Buffer I/O error on device hdb, logical block 6
Buffer I/O error on device hdb, logical block 7
Buffer I/O error on device hdb, logical block 8
Buffer I/O error on device hdb, logical block 9
/dev/hdb: read failed after 0 of 2048 at 0: Input/output error
/dev/hdb: read failed after 0 of 2048 at 528023552: Input/output error
/dev/hdb: read failed after 0 of 2048 at 0: Input/output error
No volume groups found
/dev/hdb: read failed after 0 of 2048 at 0: Input/output error
/dev/hdb: read failed after 0 of 2048 at 0: Input/output error
/dev/hdb: read failed after 0 of 2048 at 528023552: Input/output error
/dev/hdb: read failed after 0 of 2048 at 0: Input/output error
Unable to find volume group “VolGroup00”
Unable to access resume device (/dev/VolGroup00/LogVol01)
Mount: error No such device or address mounting /dev/root on /sysroot as ext3
Setuproot: moving /dev failed: No such file or directory
Setuproot: error mounting /proc: No such file or directory
Setuproot: error mounting /sys: No such file or directory
Switchroot: mount failed: No such file or directory
Kernel panic – not syncing: Attempted to kill init!

(and that’s all she wrote -- it freezes at that point)

plz reply me as soon as possible.

... and I believe that something is that /dev/hdb is about to fail? You're running into fatal errors while the system is trying to read from that disk during the boot process. I'd guess that "/dev/hdb" seems to have already experienced problems that have corrupted the directory structure and data.

Are you able to boot to single user level and run "fsck" for each of the filesystems/partitions defined on "hdb"? Have you tried booting from a "live" CD/DVD and tried running "fsck" on all of the hard disk partitions ("hda", "hdb", etc.)?

I hate to say this but you may be looking at a "rebuild and restore from backup" process.

Good luck...

I hope you have backups!
It looks like the harddisk is failing.
You can try booting from live cd and running fsck or copying your data off it.
I think you will need replace the hard disk and reinstall.